Determination of work place noise exposure – Consideration of measurements, calculations and uncertainty (NT TR 515)

Abstract

The aim of the present work is to prepare a Nordtest-method in two parts, namely a simple method for use to safety deputies, persons in industrial or occupational hygiene or in occupational health care etc., and a more advanced method requiring a great deal of competence in acoustics in order to achieve better accuracy in measurement results, if needed. The methods have to describe sources for errors and uncertainty, show how large these may be, and give guidance on how to handle the errors in order to get a most correct description of the noise situation at the work place. Second aim of this project has been to develop method(s) of calculation and measurement of work place noise exposure that are based on extensive platform from the Nordic countries. The sources for errors and uncertainty are described. It is shown how to calculate how large these may be. Guidance is given on how to handle the errors or calculate uncertainty. There is a great hope to achieve an agreement on improved Nordtest method(s) that may be applied in all Nordic countries. Measurements inside hearing protectors at some ear canal position by using of miniature microphones are described in EN-ISO 11904-1 for measurements at real ears [4], and in ENISO 11904-2 for manikin measurements [5]. These measurements are therefore not described in the scope of the present project, but they are considered to be adequate for such measurements. The calculation of daily 8-hour exposure may be made by using the present methods. The project work does not include consideration of health risk for the workers or guidance for noise reduction measures, but the resulting methods may be used to determine the noise situation more precisely and improve the accuracy of the method(s).